Routine inspections of the concrete shield building at FirstEnergy Nuclear Operating Company’s (FENOC) Davis-Besse Nuclear Power Station conducted to date have confirmed that the building continues to maintain its structural integrity and ability to safely perform its functions.
The current inspection incorporates high-definition camera technology for examination inside of the building’s walls through a series of inspection ports – or core bores. The improved camera provides greater clarity and mobility than previously available equipment.
Since the start of the inspection, 43 of the shield building’s 82 core bores have been examined, with the remaining examinations expected to be complete in the next several weeks. The improved camera has identified three very tight, subsurface pre-existing cracks in the building that were not visible with previous inspection technology. These inspections also have found that in three locations, cracks initially identified in 2011 appear to have propagated a small amount.
“Analysis of all inspection results to date confirms the 2011 conclusion that the shield building’s structural integrity is not impacted by the presence of these tight cracks. The robust building continues to function safely and reliably,” said Davis-Besse Site Vice President
Ray Lieb. “Long-term safe, reliable operation of the plant is our number one goal.”
The 2½ -foot thick reinforced concrete shield building provides biological shielding and protection from natural phenomenon including wind and tornados. The building surrounds a 1½-inch carbon steel vessel containing the reactor.
The initial cracks in the shield building were discovered in October 2011 when the building was opened to install a new reactor head. Extensive analysis conducted at the time determined that the building’s structural integrity was not affected. Subsequently, the shield building was painted with a protective coating, and a long-term inspection program was established to ensure continued safe function of the building.
Davis-Besse is part of FirstEnergy Nuclear Operating Company, a subsidiary of FirstEnergy Corp. (NYSE: FE), which also operates the Beaver Valley Power Station in Shippingport, Pennsylvania, and the Perry Nuclear Power Plant in Perry, Ohio.